Cheapest & Easiest Non-Audio Bandpass for Lighting Controller

[beatpoet]

Just to warn everyone, I'm just a hobbyist...  ;D

I am going to try to build a controller that sends signals down a single cable to a bank of solid-state switches, which in turn will run a lighting relay. This single cable format is a necessity for what I am doing, as I am using an audio signal.

What I want to do is put band-pass filters on the switching end, so the signal frequency will determine which switch is activated. These signals will be in the audio-frequency range. I will only have to have three bands: X < 500Hz, 600Hz > X > 2kHz, and X > 3kHz.

Since I am not concerned about the sonic integrity of the filters, I thought I might ask if anyone has ideas on how to build the filter out of the cheapest, most readily-available parts.

The signal output stage will be a headphone-level out.

 

[abbey road d enfer]

This is the easiest
http://www.qsl.net/zl1wtt/pdf/NE567.pdf
You don't even need a filter

 

[tv]

Google the "google images" for "light organ" or "color organ".

F.e.:
http://www3.telus.net/chemelec/Projects/Car-Color-Organ/Car-Color-Organ-5.png
http://www.redcircuits.com/Page131.htm

etc. ...

 

[Speedskater]

I built a "Color Organ" 40 years ago.  Lots of bands tried to blow it up at a friend's club, but it still works with the Christmas tree.
Anyway it didn't use filters. It had oscillators set with not quite enough feed-back to oscillate, when the correct frequency signal came along that channel would light.

 

[tv]

one-transistor twin-tee's?

 

[structuredloud]

Might be off topic, but building a box that transmits DMX protocol is pretty easy using a microcontroller and a max481 chip. Then you can hook up any old set of buttons to a dimmer pack or get REALLY fancy with all that new fangled RGB color mix lighting.

 

[mobyd]

One possibility - use a $5 phone as your sender and a DTMF decoder chip (MC145436 or its Mitel equivalent) as your reciever.
M